Even a dead Boonen with two broken legs would still outsprint a fresh Stannard in the final. Their best bet in the final against a fresh Stannard was always Boonen beating him in a sprint. Terpstra's move wasn't the most optimal move imo, but of course there's no doubt that Boonen's attack was a billion times worse. He made the biggest of all mistakes in the final, though Vandenbergh did try his best to rival him. I think it's obvious from how they rode the final that they don't completely trust each other and put the team's success ahead of their own (The last point is regarding Boonen and Terpstra, Vandenbergh is very loyal, though I do think he isn't the smartest, even for Quick Step standards).